Electric water heating apparatus for a drip coffee maker

Abstract

An electric automatic water heating apparatus for drip type beverage, e.g., coffee makers has a housing provided with a reservoir composed of a material of low thermal conductivity arranged to supply water by gravity to a sealed heating chamber having an inlet communicating with the reservoir and an outlet for discharging heated water for use. The sealed heating chamber includes an open top, cup-shaped, metallic casting having an electric rod-type resistance heating element embedded therein, and a metallic cover member closing the open top of the casting for confining steam generated during heating to the heating chamber. The cover is secured to and forms a bottom surface portion of the reservoir exposed to the water in therein. The cover serves as a support for a bimetallic member which controls the flow of water through the inlet into the heating chamber in response to the temperature in the heating chamber. Seals are provided between the heating chamber and housing for blocking flow of steam or water from the heating chamber into the housing area containing electrical components.

What is claimed is: 
     
       1. An electric automatic water heating apparatus comprising: a housing having an area containing electrical components,   a reservoir in said housing for receiving and holding water to be heated, said reservoir being composed of a material of low thermal conductivity,   a sealed heating chamber in said housing having a water inlet means in fluid communication with said reservoir for receiving water by gravity and an outlet for discharging heated water for use,   said sealed heating chamber comprising an open tip heating member of high thermal conductivity for receiving and heating water from said reservoir,   a heating element embedded in said high thermally conductive heating member, and   a high thermal conductivity cover member secured to and covering the open top of said heating member and adapted to confine steam generated during heating to said sealed heating chamber,   said cover member being secured to said reservoir,   means for blocking the flow of steam or water from said sealed heating chamber into said housing area containing electrical components,   said cover member having a first surface exposed to any water present in said reservoir and forming a bottom surface portion of said reservoir, said cover member including said water inlet means, and   flow control means including a temperature sensing element for controlling the flow of water from said reservoir through said water inlet means into said sealed heating chamber in response to the sensed temperature in said sealed heating chamber.   
     
     
       2. Apparatus as claimed in claim 1 including a resilient seal means between said cover member and said heating member. 
     
     
       3. Apparatus as claimed in claim 2 including means to clamp said heating member to said cover member. 
     
     
       4. Apparatus as claimed in claim 3 wherein said clamp means comprises a plate engaging said heating member and fastening means securing said plate to bias said heating member toward said cover member. 
     
     
       5. Apparatus as claimed in claim 1 wherein said means for blocking the flow of steam or water from said sealed heating chamber comprises a seal between said sealed heating chamber and said housing. 
     
     
       6. Apparatus as claimed in claim 5 wherein said seal between said sealed heating chamber and said housing comprises a resilient seal surrounding an outlet from said sealed heating chamber. 
     
     
       7. Apparatus as claimed in claim 1 wherein said thermally conductive cover member is mechanically secured to said reservoir, and said thermally conductive heating member is sealed to said cover member by a resilient seal means. 
     
     
       8. Apparatus as claimed in claim 1 wherein said thermally conductive heating member comprises a metallic casting and said heating element is an electrical resistance rod-type heating element embedded within said casting. 
     
     
       9. Apparatus as claimed in claim 8 wherein said inlet means and said outlet are horizontally offset from each other to provide a partially horizontal flow path for the water from said inlet means to said outlet within said sealed heating chamber, and means for deflecting the flow of water away from a direct path between said inlet means and said outlet. 
     
     
       10. Apparatus as claimed in claim 9 wherein said means for deflecting the flow of water comprises a standpipe through a central aperture forming said outlet in a well bottom of said sealed heating chamber and a barrier means between said inlet means and said standpipe to further deflect the flow of water from a direct path between said inlet means and said outlet. 
     
     
       11. Apparatus as claimed in claim 1 wherein said water inlet means comprises a first opening for the flow of water from said reservoir into said sealed heating chamber, and said flow control means comprises a first bimetallic member for controlling the flow of water through said first opening. 
     
     
       12. Apparatus as claimed in claim 4 wherein said first bimetallic member is supported by said cover member and said water inlet means comprises a perforation through said first bimetallic member in alignment with said first opening to permit a trickle flow of water into said sealed heating chamber when said sealed heating chamber is unheated, said perforation being smaller than the open area of said first opening. 
     
     
       13. Apparatus as claimed in claim 4 wherein said first bimetallic member is supported by said cover member and controls fluid flow through said first opening, and said water inlet means further comprises means defining a second opening in said cover member, and said flow control means furhter comprises a second bimetallic member secured to said thermally conductive heating member for controlling fluid flow through said second opening, said second bimetallic member being directly responsive to heat transferred from said thermally conductive heating member to initiate fluid flow through said second opening into said sealed heating chamber to thereby raise the temperature in said sealed heating chamber to thereby actuate said first bimetallic member to initiate and control fluid flow through said first opening. 
     
     
       14. An electric automatic water heating apparatus comprising: a housing having an area containing electrical components,   a reservoir in said housing for receiving and holding water to be heated, said reservoir being composed of material of low thermal conductivity,   a sealed heating chamber in said housing having a water inlet means in fluid communication with said reservoir for receiving water by gravity and an outlet for discharging heated water for use,   said sealed heating chamber comprising an open top heater casting of high thermal conductivity for receiving and heating water from said reservoir,   a heating element embedded in said heater casting, and   a cover member of high thermal conductivity secured to and covering the open top of said heater casting and adapted to confine steam generated during heating to said sealed heating chamber,   said cover member being secured to said reservoir,   first means for sealing said heater casting and said cover member to seal the perimeters of said cover member and said heater casting to one another,   means to clamp said first sealing means between said heater casting and said cover member,   second means for sealing an outlet from said sealed heating chamber to said housing to block the flow of steam into said housing area containing electrical components,   said cover member having a first surface exposed to any water present in said reservoir and forming a bottom surface portion of said reservoir, and   flow control means comprising a bimetallic member for controlling the flow of water from said reservoir through said water inlet means into said sealed heating chamber in response to the sensed temperature in said sealed heating chamber.